Matrix assisted laser desorption substrates for biological and reactive samples

Abstract

A substrate for matrix assisted laser desorption ionization mass spectrometry. The substrate has a layer of a nitride composition on the surface of the substrate. The nitride composition is a major amount by weight from the group of titanium nitride, zirconium nitride and hafnium nitride.

What is claimed is:  
     
       1. A substrate for matrix assisted laser desorption ionization mass spectrometry comprising: 
       (a) a body having a supporting surface; and  
       (b) a layer of nitride composition fixed to said supporting surface, said nitride composition being a major amount by weight from the group of titanium nitride, zirconium nitride and hafnium nitride.  
     
     
       2. The substrate as recited in  claim 1 , wherein said supporting surface is stainless steel. 
     
     
       3. The substrate as recited in  claim 1 , wherein said nitride composition is titanium nitride. 
     
     
       4. The substrate as recited in  claim 1 , wherein said nitride composition is zirconium nitride. 
     
     
       5. The substrate as recited in  claim 1 , wherein said nitride composition includes a minor amount by weight of an element other than titanium, zirconium and hafnium that is capable of forming a nitride. 
     
     
       6. The substrate as recited in  claim 5 , wherein said element is aluminum. 
     
     
       7. The substrate as recited in  claim 5 , wherein said element is carbon. 
     
     
       8. The substrate as recited in  claim 5 , wherein said element is chronium. 
     
     
       9. The substrate as recited in  claim 1 , wherein said nitride composition has a surface hardness of at least 2000 kg/mm Knoop or Vicker Microhardenss. 
     
     
       10. The substrate as recited in  claim 1 , wherein said nitride composition has an electrical resistivity no greater than 10 −1  ohm-cm. 
     
     
       11. The substrate as recited in  claim 1 , wherein said layer of nitride composition is fixed to said supporting surface by an intermediate layer of material. 
     
     
       12. The substrate as recited in  claim 11 , wherein said intermediate layer of material is metal. 
     
     
       13. The substrate as recited in  claim 11 , wherein said body is aluminum and said intermediate layer of material is electroless nickel. 
     
     
       14. The substrate as recited in  claim 11 , wherein said supporting surface is glass and said intermediate layer of material is titanium. 
     
     
       15. A method of producing a substrate for biological and reactive samples on a supporting surface in a mass spectrometer, said method comprising applying a layer of a nitride composition on said supporting surface, said nitride composition being a major amount by weight from the group of titanium nitride, zirconium nitride and hafnium nitride. 
     
     
       16. The method as recited in  claim 15 , wherein said supporting surface is stainless steel. 
     
     
       17. The method as recited in  claim 15 , wherein said nitride composition is titanium nitride. 
     
     
       18. A method of producing a substrate for biological and reactive samples in a mass spectrometer, said method comprising: 
       (a) depositing on a supporting surface of the substrate a layer of an elemental material from the group of titanium, zirconium and hafnium; and  
       (b) exposing said elemental material to nitrogen under reactive conditions to convert said layer into a nitride composition.  
     
     
       19. The method as recited in  claim 18 , wherein said depositing comprises evaporating. 
     
     
       20. The method as recited in  claim 18 , wherein said depositing comprises sputtering. 
     
     
       21. The method as recited in  claim 18 , wherein said depositing comprises electroplating. 
     
     
       22. The method as recited in  claim 18 , wherein said depositing comprises vapor deposition. 
     
     
       23. The method as recited in  claim 18 , wherein said depositing comprises physical vapor deposition. 
     
     
       24. The method as recited in  claim 18 , wherein said exposing step comprises exposing said elemental material exposing to a glow discharge plasma that includes nitrogen gas. 
     
     
       25. The method as recited in  claim 18 , wherein exposing comprises: 
       (a) creating a sub-atmospheric pressure gas mixture that includes nitrogen; and  
       (b) applying a voltage to said gas mixture to form a glow in said gas mixture and cause said nitrogen gas to react with said elemental material.  
     
     
       26. Apparatus for providing an ionized sample of material to an analysis instrument, the apparatus comprising: 
       (a) a substrate for holding a specimen of material from which said sample is derived, said substrate having a body that has a supporting surface and a layer of nitride composition fixed to said supporting surface, said nitride composition being composed of a major amount by weight from the group of titanium nitride, zirconium nitride, and hafnium nitride;  
       (b) light means directed at said layer for illuminating said specimen to cause desorption of material from the specimen to form ions of said material; and  
       (c) an interface for capturing said ions and for delivering said ions to said analysis instrument.  
     
     
       27. The apparatus as recited in  claim 26 , wherein said nitride composition is primarily by weight titanium nitride. 
     
     
       28. The apparatus as recited in  claim 26 , wherein said nitride composition is primarily by weight zirconium nitride. 
     
     
       29. The apparatus as recited in  claim 26 , wherein said nitride composition has an electrical resistivity no greater than 10 −1  ohm-cm. 
     
     
       30. The apparatus as recited in  claim 26 , wherein said nitride composition includes a minor amount by weight of an element other than titanium, zirconium, and hafnium that is capable of forming a nitride. 
     
     
       31. The apparatus as recited in  claim 26 , wherein said light means is a laser. 
     
     
       32. The apparatus as recited in  claim 26 , wherein said interface comprises: 
       (a) a housing having a first vacuum chamber and a second vacuum chamber adjacent said first vacuum chamber;  
       (b) a sample capillary extending from said substrate to said first vacuum chamber for conveying said ions to said first vacuum chamber;  
       (c) a skimmer between said first vacuum chamber and said second vacuum chamber for directing said ions into said second vacuum chamber; and  
       (d) ion optics located in said second vacuum chamber for focusing said ions to said analysis instrument.  
     
     
       33. A mass spectrometer comprising: 
       (a) an analysis instrument for analyzing an ionized sample of material;  
       (b) a substrate for holding a specimen of material from which said sample is desired, said substrate having a body that has a supporting surface and a layer of nitride composition fixed to said supporting surface, said nitride composition being composed of a major amount by weight from the group of titanium nitride, zirconium nitride, and hafnium nitride;  
       (c) light means directed at said layer for illuminating said specimen to cause desorption of material from the specimen to form ions of said material; and  
       (d) an interface for capturing said ions and for delivering said ions to said analysis instrument.  
     
     
       34. The mass spectrometer as recited in  claim 33 , wherein said nitride composition is primarily by weight titanium nitride. 
     
     
       35. The mass spectrometer as recited in  claim 33 , wherein said nitride composition is primarily by weight zirconium nitride. 
     
     
       36. The mass spectrometer as recited in  claim 33 , wherein said nitride composition has an electrical resistivity no greater than 10 −1  ohm-cm. 
     
     
       37. The mass spectrometer as recited in  claim 33 , wherein said nitride composition includes a minor amount by weight of an element other than titanium, zirconium, and hafnium that is capable of forming a nitride. 
     
     
       38. The mass spectrometer as recited in  claim 33 , wherein said light means is a laser. 
     
     
       39. The mass spectrometer as recited in  claim 33 , wherein said interface comprises: 
       (a) a housing having a first vacuum chamber, a second vacuum chamber, and third vacuum chamber which contains said analysis instrument, said second vacuum chamber being located between said first vacuum chamber and said third vacuum chamber;  
       (b) a sample capillary extending from said substrate to said first vacuum chamber for conveying said ions to said first vacuum chamber;  
       (c) a skimmer between said first vacuum chamber and said second vacuum chamber; and  
       (d) ion optics located in said second vacuum chamber, said ion optics extending from said skimmer and into said third vacuum chamber to said analysis instrument for focusing said ions to said analysis instrument.